(a) Technical Field
The present disclosure relates to a display device and a driving method thereof.
(b) Discussion of Related Art
Liquid crystal display panels are one type of flat panel displays that are being used widely, and typically include two display panels that have a field generating electrode, such as a pixel electrode, a common electrode, and a liquid crystal layer interposed therebetween. The liquid crystal display supplies voltage to the field generating electrode, and then forms an electric field on the liquid crystal layer, thereby determining the direction of liquid crystal molecules on the liquid crystal layer and displaying an image by controlling the polarization of incident light. In addition to the liquid crystal display, the flat panel display panel include an organic light emitting diode (OLED) display, a plasma display panel (PDP), an electrophoretic display device, and the like.
The display device typically includes a display panel having pixels that include switching elements and display signal lines such as gate lines and data lines, a gate driver that turns on/off the switching element of the pixel by transmitting gate signals to the gate lines, a data driver that supplies data voltage to the data lines, a signal controller that controls the gate driver and the data driver.
The gate signal that is supplied to the gate line by the gate driver which is configured such that a gate-on voltage Von turns on the switching element of the pixel and a gate-off voltage Voff turns off the switching element of the pixel.
The gate driver and the data driver may be mounted in the display device in a type of IC chip, attached on the display device in a type of tape carrier package (TCP) by being mounted on a flexible printed circuit film, or mounted on a printed circuit board. Particularly, the gate driver may be integrated in the display panel by the same process that is used for the display signal line, the switching element, and the like.
When integrating the gate driver in the display panel, a lower voltage than the gate-off voltage Voff is needed to supply the gate-off voltage Voff to the gate line. Hereinafter, such voltage lower than the gate-off voltage Voff is called a second gate-off voltage Voffe.
However, the gate-off voltage Voff may be unstable as a result of the interconnection of the gate-off voltage Voff and the second gate-off voltage Voffe. A change of the gate-off voltage Voff may be further intensified when the display panel becomes larger or the display device is driven at a low temperature.